You can get a small car from priceline.com for under $25/day depending on the time of year of your visit...that's practically the cost of a single taxi ride.
I don't know of any local taxi companies besides the company that runs the Windsor Hills shuttle service....here's the info on that with their phone#...you might want to call them and inquire how much other services cost.
How does the Windsor Hills Resort daily shuttle service work/operate/etc?
In the sundry shop in the Windsor Hills clubhouse you can find schedules and make arrangements. Shuttle cost is $10 per person round trip to Magic Kingdom, Epcot, MGM, or Animal Kingdom. $14 per person round trip to universal, seaworld, and shopping area. There is an information sheet at the clubhouse with the time schedule. The shuttle company is MAINGATE TRANSPORTATION. They can be called at # 407-390-0000. A taxi cab to Disney is $20 one way.. cab to Universal is $32 one way.... Don't forget it costs $10 per day for parking at Disney and Universal if you drive.